CN111512079A

CN111512079A - Compact control valve

Info

Publication number: CN111512079A
Application number: CN201880078612.9A
Authority: CN
Inventors: 利昂内尔·比耶; 米夏埃尔·德尔巴尔; 瓦朗坦·普雷奥; 格尔·安德里厄
Original assignee: Moving Magnet Technologie SA
Current assignee: Moving Magnet Technologie SA
Priority date: 2017-12-08
Filing date: 2018-12-05
Publication date: 2020-08-07
Anticipated expiration: 2038-12-05
Also published as: WO2019110923A1; FR3074872A1; FR3074872B1; US11329531B2; US20210175777A1; KR102613654B1; KR20200093042A; EP3721123B1; JP7339947B2; JP2021505823A; EP3721123A1; CN111512079B

Abstract

The invention relates to a valve for controlling the circulation of a fluid, having a valve body (2) and a housing containing an electric motor comprising a stator and a rotor, a needle, a sealing bell and a fixing screw or nut fixed to the valve body, the stator being fixed to the valve body by said housing, the sealing bell being positioned at the junction between the rotor and the stator so that said screw/nut, rotor and needle are inside the housing and immersed in said fluid, the stator being isolated from said fluid, the rotor having the function of a nut or screw and having the helical motion imparted by said fixing screw or nut and driving said needle axially, characterized in that the electric motor is a brushless electric motor with a radially main magnetic flux.

Description

Compact control valve

Technical Field

The present invention relates to a compact control valve for use in, for example, a pressure regulator of an air conditioning circuit and which is actuated by a brushless electric motor.

The invention is preferably used in the field of, but not limited to, flow control valves for air conditioning or battery cooling circuits. The particularity of these systems is the need to keep the heat transfer fluid in a sealed circuit. In order to ensure such sealing while allowing a permanent actuation, the solution generally adopted is to separate the fixed part of the solenoid of the brushless electric motor or generally of the stator of the motor, which is not immersed in the fluid, from the movable element moving in the fluid circuit, this separation being performed by the sealed non-magnetic element. The flow can thus be controlled without affecting the sealing of the refrigeration circuit. These regulation systems are required to be very compact, energy efficient, control accurate and able to adapt to the various mechanical configurations of the fluid circuit.

Due to new environmental standards and the demands related to vehicle electrification for obvious reasons of comfort, efficiency and sometimes risk, the increasing demands on the accuracy and safety of the handling of the entire air conditioning system have put demands on the feedback of the position of the control needle of these expansion valves. Due to the need for energy efficiency, it is also desirable to detect the position of the active portion of the valve during control.

The force required during control is relatively high with respect to the volume of the system, which has a maximum value in the case of a needle resting on a valve seat when the heat transfer fluid circuit is closed. On a redundant possible displacement of the needle, the force is reduced and the fluid passage cross section becomes larger and larger. Therefore, for the purpose of optimized power consumption, it is advantageous to adjust the force in dependence on the position of the active part of the valve.

Finally, these systems are present in the field of industry or houses, but also in the field of motor vehicles where compact integration is required. Therefore, it is necessary to actually and integrally fix the actuator to the valve body.

Background

In the earliest documents, expansion valves comprising radial flux electric motors were known from us patent No. 4650156. During operation, the rotor is displaced helically, the rotor being guided by a screw-nut system, the screw portion being fixed to the rotor, the nut portion being fixed and associated with the heat transfer fluid circuit. The helical movement of the rotor is useful only by the linear displacement of the rotor, which is transmitted to the needle and makes it possible to control the flow of the fluid that has to pass in the gaseous phase and therefore the cooling level of the system. Sealing is achieved by a system incorporating a stator and a rotor immersed in a fluid.

In this same document, the axial length of the rotor is shorter than the axial length of the stator. During the displacement, the rotor portion carrying the magnets remains opposite the magnetically conductive material of the stator, the torque generated by the motor thus remaining constant throughout the stroke. The force generated is therefore also constant over the actuator stroke. This embodiment has a problem in terms of axial dimension: in addition to the fact that the axial height of the stator is greater than the rotor, guidance on both sides of the rotor is required.

In the prior art, there is also a method for directly fixing an electrical part that is translated by means of a screw on a mechanical part dedicated to the passage of a heat transfer fluid, in document JP 996210733. This allows to mount the electrical components in an angular position in a simple and free way, but it is only applicable to directly actuated solenoids having a non-circular shape. Consequently, the dimensions and performance are not optimal and there are connections that force the mechanical functions to be axially stacked, which is still detrimental to the compactness of the assembly.

Recently, in order to solve the above mentioned problems, application US2009/0294713 introduces a set screw and a guide within the rotor of the motor, but the use of a motor with transverse magnetic flux causes damage to the assembly. Transverse flux machines have two electrical phases axially stacked. The axial displacement of the rotor causes a gradual imbalance of the torque produced by each phase, so that the regularity of the total torque and therefore the performance is degraded. In addition, stacking of lateral motor phases is detrimental to axial compactness.

The motor with transverse magnetic flux has two coils describing a torus with its axis parallel to the main axis of motion, here in switching relationship with the screw nut. The set screw, joined to the portion associated with the coolant inlet, is in the shape of a solid of revolution and is hollow along the main axis of movement, allowing the flow control needle to pass, the nut being mechanically joined to the rotor of the motor. The rotor of the motor is displaced in a helical manner during operation of the expansion valve. It should be noted that the axial length of the rotor is shorter than the axial length of the stator portion, as in us patent No. 4650156.

More recently, document US9525373 describes an angle sensor associated with a valve equipped with a motor with transverse magnetic flux, a fixed part surrounding a sealing bell describing a rotating annular shape coaxial with respect to the axis of the valve and having a lateral outlet. However, this sensor is only used to detect a stop caused by a loss of synchronism between the moving part of the sensor and the rotor part of the actuator, and is not used for the measurement of the absolute angular position of the rotor. Considering the strong influence of the motor coils on the above mentioned hall effect sensors, the sensor performance should be poor.

Technical problem

The purpose of these devices is to solve the general problem of linearly controlling the flow of a fluid, such as a heat transfer fluid, by associating an electromechanical system with the fluid circuit.

However, the previously described devices always have a structure that results in a large axial dimension with a translation of the movement and guiding elements located axially on either side of the electric motor, or a configuration of a transverse flux electric motor comprising two superposed coils.

The use of motors with transverse magnetic flux is undesirable from the point of view of having an analogue position sensor, i.e. giving information proportional to the displacement, because the magnetic flux generated by these coils is well above the motor and therefore when the sensor is a magneto-sensitive sensor, the magnetic flux can interfere with the performance of the sensor. Additionally, in any of these patents, the sensor is not used to measure axial displacement of the needle or rotor. The electromagnetic solutions of patent JP996210733 and of application US2009/0294713 are both magnetic topologies with axial magnetic flux, generating a magnetic field along the axis of displacement and interfering with any magneto-sensitive sensor.

In us patent No.4650156, the use of sensors is not described and the solution used discourages the use of sensors. The entire motor is immersed in the fluid and, plus the sensors, control circuitry and printed circuitry, will cause leakage and connection output problems.

In terms of the size of the solution, the solutions using motors with axial magnetic flux generally have a lateral output connector, which results in a larger contact area and larger size. If a position sensor is used near the axis of the needle, the electrical and mechanical connection of the different elements will be problematic due to the distance between the connectors of the two components.

Disclosure of Invention

The present invention aims to overcome the disadvantages of the prior art by making the actuator more compact and efficient than prior art actuators.

It is also an object of the invention to optionally allow the use of a position sensor integrated into the motor and this makes it possible to determine the linear position of the needle.

The object of the invention is also to allow the use of a position sensor integrated in the motor and which makes it possible to determine the angular position of the rotor of the motor.

The invention also aims to allow an easy and secure fixing of the motor to the valve body without using welding and within limited dimensions.

According to a particular embodiment, the invention relates to a device comprising an electric motor that is not perfectly cylindrical, making it possible to clear the area where the fixing device can be integrated, without interfering with the coils of the electric motor.

According to other particular embodiments, the invention relates to a device comprising an electric motor that is not perfectly cylindrical, so that the area in which the device can be integrated can be cleared without interfering with the coils of the electric motor, and outside the volume described by the housing carrying the stator part. Thus facilitating the sealing of the electric motor against the outflow of external fluid.

The invention also relates to the realization of a needle position sensor and a solution to improve the accuracy of an axial sensor according to the temperature variations of the fluid by introducing a heat-conducting element between the sealing bell where the part generating the magnetic field is located and the magnetic measuring probe located outside. The magnetic measuring probe may be temperature compensated by its internal construction, but it is located within the volume described by the housing, outside the bell separating the rotor from the stator, and may experience a temperature different from that of the fluid. Maximum accuracy can be achieved when the temperature gradient between the probe and the element generating the magnetic field is minimal, thereby enabling temperature compensation over more precise known field variations.

More particularly, the invention relates to a control valve for controlling the circulation of a fluid, having a valve body and a housing containing an electric motor comprising a stator and a rotor, a needle, a sealing bell and a fixing screw or nut fixed to the valve body, the stator being fixed to the valve body via said housing, the sealing bell being positioned at the junction between the rotor and the stator so that the screw/nut, the rotor and the needle are in the cage and immersed in said fluid, the stator being isolated from said fluid, the rotor having a nut or screw function and having a helical motion imparted by said fixing screw or nut and driving the needle axially, characterized in that the motor is a brushless polyphase motor with a radially main magnetic flux.

Advantageously, the control valve has a linear needle position sensor comprising: a magnetosensitive probe fixed to the housing outside the bell and detecting an axial component of a magnetic field, and at least one magnetic element fixed to the needle or the rotor inside the bell and generating the magnetic field and located inside the bell. To allow insensitivity to misalignment, the sensor may have a magnet connected to the probe outside the bell, the magnetization direction of the magnet being in the axial displacement direction of the needle and having the same orientation as the magnetization direction of the magnetic element.

In another embodiment of the linear needle position sensor, the linear needle position sensor comprises: a magnetosensitive probe fixed to the housing outside the bell and detecting the axial component of the magnetic field, at least one magnet fixed to the probe outside the bell and generating a magnetic field, and a magnetic element in the form of a soft ferromagnetic piece fixed to the needle and located inside the bell and varying the characteristics (intensity, direction, etc.) of the magnetic field emitted by the magnet at the level of the probe.

In these sensor solutions, the probe is alternatively positioned near a bell and a heat conducting element is placed at the junction between the probe and the bell.

The valve may alternatively have a rotor angular position sensor comprising: a magnetosensitive probe that detects and processes the phases of two cartesian components of the magnetic field in a plane orthogonal to the axial displacement axis of the needle and close to the rotation axis of the motor or of a magnetic vector in a plane orthogonal to the axial displacement axis of the needle and close to the rotation axis of the motor, said probe being located outside said bell; and at least one magnetic element that generates the magnetic field, is located within the bell, and is fixed to the rotor.

In this case, the magnetic element emitting the magnetic field is, for example, an axial dipole magnet.

In order to allow the actuator to be fixed to the valve body, the invention also relates to a valve body having a flat receiving surface, and a housing fixed to the valve body on the receiving surface by axial fixing means, the stator having a triangular shape and having at least one fixing element arranged between the vertices of the triangular shape.

In this case, the fixing elements are at least partially alternately located in a circle passing through said apex of the triangular shape, or the stator has an at least partially circular outer shape, and at least one fixing element is arranged outside the stator part of the motor and at least partially within the circle inscribed on the stator.

Drawings

Other features and advantages of the present invention will become apparent upon reading the following detailed description in conjunction with the accompanying drawings, in which:

figure 1 is a perspective view of a valve according to the invention in a first embodiment of the invention;

figure 2 is a top view of the device of figure 1 without the cover;

FIG. 3 is a longitudinal section and an enlarged area view of the device of FIG. 1;

figure 4 is a partially cut-away perspective view of the device of figure 1;

figure 5 is a view of the valve according to the invention in a second embodiment of the invention, in which the electric motor has a greater number of coils than in the first embodiment;

FIG. 6 is a top view and a cross-sectional view of the device of FIG. 5;

figure 7 is a detailed cross-sectional view in the longitudinal direction of a solution with an alternative to the position sensor used in the present invention;

figure 8 is a detailed cross-section in the longitudinal direction of an alternative embodiment in which the rotor forms a screw and the sensors used have inductive physics.

Detailed Description

Figure 1 shows an isometric view of a first embodiment of a valve according to the present invention, which associates an electric actuation assembly and a mechanical assembly to form a circulation path for a heat transfer fluid. The valve therefore comprises more specifically an electric actuator (1) which translates a needle (not visible here) along a displacement axis (3) by using an electric motor. The actuator (1) is fixed to a valve body (2) comprising a passage (25) for a heat transfer fluid, the flow of which is commanded by said needle. The electric actuator (1) comprises a cover (24) on the upper part and the electric actuator (1) is fixed to the valve body (2) by axial fixing means (4), such as screws or bolts.

Fig. 2 is a plan view of the first embodiment without the cover, and this view makes it possible to understand the electric actuator with radial magnetic flux that is generally used in the present invention. The actuator (1) has a stator (6) formed by stacked cores forming teeth, on some of which electrical coils (8), here three coils at 120 ° to each other, are arranged. The particular shape of the stator, here triangular, makes it possible to house the axial fixing element (4) without increasing the total contact area (2) of the actuator on the valve body. The freedom of angular positioning of these elements allows to easily orient the actuator, in particular the connector (5) of the actuator, according to the needs of the whole air conditioning system. Thus, the simple flat contact area of the valve body (2) allows to receive such an actuator without rotational symmetry. In particular, a circle (7) inscribed in the triangular shape of the stator (6) intersects the fixing element (4) virtually and in axial projection. The actuator (1) is enclosed by a housing (9), which may be a housing in which the actuator (1) is placed, or other overmolded plastic material. In this view without the cover (24), the presence of a sealing bell (16) is also understood, inside which the rotor of the actuator (1) and the needle to be displaced are housed, these elements being immersed in the heat transfer fluid. The stator (6) and the coils (8) are external to the bell and isolated from the heat transfer fluid.

Fig. 3 shows a longitudinal section of the valve according to this first embodiment. The actuator (1) is screwed onto the valve body (2) by using a fixing element (4). The valve body (2) has heat transfer fluid inlet and outlet circulation channels (25). The fluid passage (1) is controlled by positioning the end of the needle (11) operated by the electric actuator (1) along the axis (3) so as to move the end of the needle (11) closer to or away from the needle seat (17). The rotor (12) comprises a nut portion (14) and in this particular embodiment the rotor (12) here also forms a support for a yoke and a permanent magnet (13), the rotor bringing the needle (11) into motion by means of a connection which is here fixed but can be indirectly connected via a spring at a joint (not shown). The nut part (14) may be ferromagnetic in order to allow guiding the magnetic flux of the magnet (13), and the nut part (14) has a mechanical function in order to ensure the feasibility of the movement transformation. The movement of the rotor (12) and therefore of the needle (11) follows a helical trajectory, thus combining the rotation of the motor formed by the rotor (12) and the stator (6) and the translation imposed by screwing the nut portion (14) onto (here) the fixing screw (15) and to the valve body (2). The motion is helical, but for valve control only the translating part is mechanically important, where the needle has the geometry of a solid of revolution.

In this embodiment, the axial height of the rotor (12) is smaller than the axial height of the stacked cores (10), so that during the displacement of the rotor in its helical movement, the rotor always faces radially towards the stator, wherein the linear stroke S of the rotor is defined in fig. 3 and 7. In the case of fig. 3, the valve is shown in the closed position and the rotor can be returned into the stator without changing the effective surfaces between the rotor and the stator that face each other. Thus, the torque generated by the motor and thus the force applied to the needle (11) is not affected during displacement. It should be noted that if it is desired to optimize the effective height, it may be considered to increase the height of the magnets to be greater than or equal to the height of the superposed cores (10) of the stator (6), as shown in fig. 7, which optionally allows to adjust the force for the same electrical control current. The active surface between the rotor and the stator can then be scaled when the needle (11) is lifted, which generates a variable force when the valve is opened, so that the actuator can be adapted to a reduction in the pressure applied to the needle (11).

The construction shown here is particularly compact in the axial direction, wherein a guide is provided in the entire effective height of the stacked cores (10), this guide being produced here by the engagement of the screw (15) with the nut (14) and by the engagement of the body of the needle (11) with the inner surface of the fixing screw.

In this configuration of fig. 3, the needle (11) position sensor is shown, since the use of a radial flux actuator makes this easier. The magnetic principle sensor is located above the rotor (12) on the upper part of the valve. The magnetized magnetic element (20a) is connected to the nut portion (14), thus to the rotor (12) and thus to the needle (11). The magnet, which has an axial magnetization along the axis (3), is also placed in the bell (16). During the helical displacement of the rotor (12), the magnetic element (20a) thus moves away from or close to the bottom of the bell (16). Opposite the bell (16) or outside the bell (16) on the axis (3) there is positioned a magnetosensitive probe (19) which detects the amplitude of the axial component of the magnetic field emitted by the magnetic element (20a) on the axis (3). Thus, the magnetic element (20a) is far from or close to the magnetosensitive probe (19) so that the amplitude of the field detected by the probe (19) can be adjusted and an image of the position of the needle (11) can be given. Here, the axis of axial sensitivity of the probe (19) is important, since the motor with radial magnetic flux generates a magnetic field on the axis (3) whose axial component is much lower than the axial component of the magnetic field generated by the motor with transverse magnetic flux. The axial component generated here is merely a leakage, which is the primary path of the prior art motor.

The probes (19) are carried by a printed circuit (18) located above the bell (16) and below the cover (24). The printed circuit (18) also carries the connection points to the coils (8) of the actuator (1) and the electronic components required to control the polyphase electric motor. The printed circuit (18) also supports a compensation magnet (21) surrounding the probe (19), which compensation magnet (21) can optionally be used to control the average induction level of about zero gauss and thus improve the temperature characteristics of the sensor. In this case, the compensation magnet will have an axial magnetization direction in the same direction as the magnetization direction of the magnetic element (20 a).

The magnetic element (20a) generating the axial magnetic field is made of a neodymium-iron-boron magnet, a ferrite or a samarium-cobalt magnet. Samarium cobalt magnet material has the advantage that its magnetic properties vary very little with temperature, thus minimizing the drift of the sensor signal and minimizing the effect of the temperature gradient between the fluid and the magnetic field measurement probe.

In order to improve the temperature consistency between the magnetosensitive probes (19) located respectively outside and inside the bell (16) and the magnetic element (20a) emitting the magnetic field, and in order to allow a more efficient temperature compensation, a heat-conducting element (22) may be placed at the junction between the bell (16) and the probe (19), so that the probe (19) may reach a temperature close to the temperature inside the bell, and thus close to the temperature of the magnetic element (20 a).

Fig. 4 shows a partial cross-sectional view of this first embodiment, which makes it possible to understand in greater detail the screw (15) and the components described above, in particular variants of a position sensor which can be used, for example, to control the electric motor in a closed-loop manner, or simply to determine the position of the needle and to ensure that the needle is in the desired position, for this purpose the probe (19) can have magnetic sensitivity to the amplitude of the two components of the magnetic field orthogonal to the axis of displacement, or to the phase of the vector of the magnetic field orthogonal to the axis of displacement, in order to determine the only angular position of the rotor, the probe (19) can also have magnetic sensitivity to the amplitude of the three components of the magnetic field, or to the phase of the magnetic vector of the magnetic element (20a) in a plane orthogonal to the axis of displacement and in a plane along the axis of displacement, respectively, in order to determine both the angular position and the axial position of the rotor, the solution designed makes it possible to measure these three components of the magnetic field, for example, using a probe of the M L X90363 type makes it possible to measure the three components of the magnetic field, the rotor's amplitude, the rotor's output, which can be measured indirectly by considering the absolute magnetic field output of the rotor's (12) in relation to the two magnetic field's output's sine-output, which is possible to be obtained by an absolute-output-a-type which is clearly-a-type which is able to be measured-a magnetic field-type which is able to be measured-a-which is purely-a-type which is able to be-a-type which is able to be-a-.

In order to overcome the magnetic field generated by the stator more thoroughly, it can be considered to use a "dual mode" probe, i.e. with two adjacent magneto-sensitive elements, within the framework of a differential measurement. A shield located near the coil in order to short-circuit stray magnetic fields emitted by the coil and/or near the probe also constitutes a more reliable solution.

Fig. 5 shows a second variant of use in which the motor uses a number of electrical coils greater than three (six are shown here), thus varying the external contact area of the stator. This configuration is advantageous in the case where the force requirements relating to the control of the fluid, more precisely due to the pressure differences between the various elements of the fluid circuit, are significant. For a given electrical power at the input of the actuator, an increase in the number of coils increases the force factor produced by the actuator.

This second variant also differs from the first in that the housing (9) has a substantially tubular shape with two axial gaps (26) at the periphery in order to allow fixing using the fixing element (4).

Fig. 6 shows a detail of the magnetic circuit of the actuator (1), the fixed element (4) being located inside a circle (23) inscribed on the outside of the stator and between the six coils (8) of the stator part. The number of fixing elements (4) is not limited. Two fixation elements are shown here, but more than two fixation elements are contemplated. Thus, the total contact area of the actuator with the fixed element (4) of the actuator is minimized over the rectangular shape of the valve body and valve body. Furthermore, the orientation of the connector (5) may vary due to the positioning principle and the chosen fixing elements.

The probe (19) is shown isolated at a preferred position above the stator on the displacement axis (not shown here).

Fig. 7 shows an alternative embodiment of the position sensor. In this embodiment of the sensor, the magnetic element (20b) is a soft ferromagnetic element that does not emit a magnetic field but changes the intensity of the magnetic field emitted by the magnet (21) of the sensor surrounding the probe (19) and detected at the level of the probe (19) during the axial movement of the magnetic element (20 b). The magnetic elements (20b) may be located on both sides of the printed circuit (18), always outside the bell (16). The advantage of this solution is that the probe (19) and the magnet (21) of the sensor are juxtaposed so as to allow an improved compensation of the variation of the magnetic field with temperature.

Typically, the sensors described in the previous examples are integrated in the rotor, but the invention is also applicable in the case where the magnetic element (20a) or (20b) is integrated in the upper end of the needle (11).

Fig. 8 shows an alternative embodiment of a sensor that can be used, which is of inductive principle. An alternative embodiment comprises a passive magnetic element (20b) fixed to the rotor and two electrical coils (27, 28) located inside the bell. The general principle of an inductive sensor is as follows:

-the first coil (27) emits a variable magnetic field,

-the second coil (28) receives a variable magnetic field by inductive coupling,

-the magnetic element (20b) changes the inductive coupling between the coils (27, 28) when the magnetic element (20b) moves away from the coils (27, 28) or axially close to the coils (27, 28). This change in coupling causes a different response at the height of the coil (28) -for example in terms of the phase or amplitude of the detected signal-which makes it possible to relate the detected signal to the position.

Fig. 8 also shows an alternative embodiment of coupling the rotor with the valve body (2). In this example, the rotor is attached to a needle (11) forming a screw (30) which cooperates with a fixing nut (29) joined to the valve body (2). This is different from the previous example, in which the rotor forms a nut and cooperates with a fixed screw portion joined to the valve body (2). The invention is not limited by the screw/nut function, which can be performed by the rotor or at the height of the valve body (2).

In all the examples presented herein, but not exhaustive, it is evident that the sensor solution is not limited to the option of using a screw or nut at the height of the rotor or valve body (2) and that it is possible to consider adopting the sensor solution and adapting it to one of the mechanical solutions envisaged.

Claims

1. A control valve for controlling the circulation of a fluid, having a valve body (2) and a housing (9) housing an electric motor comprising a stator (6) and a rotor (12), a needle (11), a sealing bell (16) and a fixing screw or nut (15), the fixing screw or nut (15) being fixed to the valve body (2), the stator being fixed to the valve body (2) via the housing, the sealing bell (16) being positioned at the junction between the rotor (12) and the stator (6) so that the screw/nut, the rotor (12) and the needle are inside the bell (16) and immersed in the fluid, the stator (6) being isolated from the fluid, the rotor (12) having the function of a nut or a screw and having a helical motion applied by the fixing screw or nut (15) and driving the needle axially Characterized in that said motor is a brushless multi-phase electric motor having a radially main magnetic flux.

2. The control valve of claim 1, wherein the control valve has a needle linear position sensor comprising: a magnetosensitive probe (19), said magnetosensitive probe (19) being fixed to said housing externally of said bell (16) and detecting an axial component of a magnetic field; and at least one magnetic element (20a), said at least one magnetic element (20a) being fixed to said needle or said rotor (12) within said bell and generating said magnetic field.

3. The control valve of claim 1, wherein the control valve has a needle linear position sensor comprising: a magnetosensitive probe (19), said magnetosensitive probe (19) being fixed to said housing externally of said bell (16) and detecting an axial component of a magnetic field; at least one magnet (21), said at least one magnet (21) being fixed to said probe outside said bell and generating said magnetic field; and a magnetic element (20b) in the form of a soft ferromagnetic piece, said magnetic element (20b) being fixed to the needle and located inside the bell and varying the characteristics of the magnetic field emitted by the magnet at the level of the probe.

4. Control valve according to claim 2, characterized in that the sensor has a magnet (21) fixed to the probe outside the bell, the magnetization direction of the magnet (21) being in the axial displacement direction of the needle and having the same orientation as the magnetization direction of the magnetic element (20 a).

5. Control valve according to any of claims 2-4, characterized in that the probe is positioned near the bell and that a heat conducting element (22) is arranged at the junction between the probe and the bell.

6. Control valve according to any of the preceding claims, characterized in that it has a rotor (12) angular position sensor comprising: a magnetosensitive probe (19), said magnetosensitive probe (19) detecting and processing the phases of two cartesian components of a magnetic field in a plane orthogonal to the axial displacement axis of the needle and close to the rotation axis of the motor, or of a magnetic vector in a plane orthogonal to the axial displacement axis of the needle and close to the rotation axis of the motor, said probe being located outside the bell; and at least one magnetic element (20a), said at least one magnetic element (20a) being fixed to said rotor (12), generating said magnetic field and being located inside said bell.

7. Control valve according to the preceding claim, characterized in that the magnetic element emitting the magnetic field is an axial bipolar magnet.

8. Control valve according to any of the preceding claims, characterized in that the valve body (2) has a flat receiving surface and the housing is fixed to the valve body (2) on the receiving surface by means of axial fixing means (4), the stator (6) having a triangular shape and at least one fixing element being arranged between the vertices of the triangular shape.

9. Control valve according to the preceding claim, characterized in that the fixing element is at least partially located within a circle (23) passing through the apex of the triangular shape.

10. A control valve according to any of claims 1-7, characterized in that the valve body (2) has a flat receiving surface and the housing is fixed to the valve body (2) on the receiving surface by means of axial fixing means (4), that the stator (6) has an at least partly circular outer shape, and that at least one fixing element is placed outside the stator part of the motor and at least partly inside a circle (23) inscribed on the stator (6).